Frame Rating: Catalyst 13.8 Brings Frame Pacing to AMD Radeon

Frame Pacing for CrossFire

When the Radeon HD 7990 launched in April of this year, we had some not-so-great things to say about it. The HD 7990 depends on CrossFire technology to function and we had found quite a few problems with AMD's CrossFire technology over the last months of testing with our Frame Rating technology, the HD 7990 "had a hard time justifying its $1000 price tag." Right at launch, AMD gave us a taste of a new driver that they were hoping would fix the frame pacing and frame time variance issues seen in CrossFire, and it looked positive. The problem was that the driver wouldn't be available until summer.

As I said then: "But until that driver is perfected, is bug free and is presented to buyers as a made-for-primetime solution, I just cannot recommend an investment this large on the Radeon HD 7990."

Today could be a very big day for AMD - the release of the promised driver update that enables frame pacing on AMD 7000-series CrossFire configurations including the Radeon HD 7990 graphics cards with a pair of Tahiti GPUs.

It's not perfect yet and there are some things to keep an eye on. For example, this fix will not address Eyefinity configurations which includes multi-panel solutions and the new 4K 60 Hz displays that require a tiled display configuration. Also, we found some issues with more than two GPU CrossFire that we'll address in a later page too.

New Driver Details

Starting with 13.8 and moving forward, AMD plans to have the frame pacing fix integrated into all future drivers. The software team has implemented a software based frame pacing algorithm that simply monitors the time it takes for each GPU to render a frame, how long a frame is displayed on the screen and inserts delays into the present calls when necessary to prevent very tightly timed frame renders. This balances or "paces" the frame output to the screen without lowering the overall frame rate. The driver monitors this constantly in real-time and minor changes are made on a regular basis to keep the GPUs in check.

As you would expect, this algorithm is completely game engine independent and the games should be completely oblivious to all that is going on (other than the feedback from present calls, etc).

This fix is generic meaning it is not tied to any specific game and doesn't require profiles like CrossFire can from time to time. The current implementation will work with DX10 and DX11 based titles only with DX9 support being added later with another release. AMD claims this was simply a development time issue and since most modern GPU-bound titles are DX10/11 based they focused on that area first. In phase 2 of the frame pacing implementation AMD will add in DX9 and OpenGL support. AMD wouldn't give me a timeline for implementation though so we'll have to see how much pressure AMD continues with internally to get the job done.

Since that April release of the HD 7990 and today, I have had dozens of calls with AMD about their hardware, drivers and my stance on them. Even though I was told over and over again that I was wrong and that our results weren't really indicative of what end users were seeing, I stuck to our testing methods and my hands-on, real world testing experiences. When AMD promised this driver for us in the summer I was told that frame pacing would be an option you could enable in the driver but that it would be disabled by default. The reason was that they believed the old way of doing things had benefits that other users wouldn't want to give up.

Things have changed a bit.

Starting with the release of the Catalyst 13.8 beta driver and going forward, you will see a new option under the 3D settings menu called Frame Pacing. That option will be enabled by default. Why the sudden change? It would seem that after doing some more testing AMD finally agreed with us: there was no reason to NOT have it enabled! Leaving frame pacing disabled did not improve input latency and the offset of the problems of runt frames finally won over.

So other than a bit of pride and a feeling of "I told you so" floating around the office, what does it all mean for the gamer? What has changed in our experiences and metrics? That is what the rest of our story is going to deal with through a set of benchmarks and discussions.

Radeon HD 7990 13.4 vs HD 7990 13.8 - This is the biggest thing to check for and it will tell you how much improvement is made in the new 13.8 frame pacing driver. Look for more consistent frame times, thinner bands of color on those graphs.

Radeon HD 7990 13.8 vs GeForce GTX 690 - AMD likes to make claims about the "fastest graphics card" with the HD 7990 but I have never agreed with them. Does this change things in favor of AMD?

While there are literally dozens of file created for each “run” of benchmarks, there are several resulting graphs that FCAT produces, as well as several more that we are generating with additional code of our own.

The PCPER FRAPS File

While the graphs above are produced by the default version of the scripts from NVIDIA, I have modified and added to them in a few ways to produce additional data for our readers. The first file shows a sub-set of the data from the RUN file above, the average frame rate over time as defined by FRAPS, though we are combining all of the GPUs we are comparing into a single graph. This will basically emulate the data we have been showing you for the past several years.

The PCPER Observed FPS File

This graph takes a different subset of data points and plots them similarly to the FRAPS file above, but this time we are look at the “observed” average frame rates, shown previously as the blue bars in the RUN file above. This takes out the dropped and runts frames, giving you the performance metrics that actually matter – how many frames are being shown to the gamer to improve the animation sequences.

As you’ll see in our full results on the coming pages, seeing a big difference between the FRAPS FPS graphic and the Observed FPS will indicate cases where it is likely the gamer is not getting the full benefit of the hardware investment in their PC.

The PLOT File

The primary file that is generated from the extracted data is a plot of calculated frame times including runts. The numbers here represent the amount of time that frames appear on the screen for the user, a “thinner” line across the time span represents frame times that are consistent and thus should produce the smoothest animation to the gamer. A “wider” line or one with a lot of peaks and valleys indicates a lot more variance and is likely caused by a lot of runts being displayed.

The RUN File

While the two graphs above show combined results for a set of cards being compared, the RUN file will show you the results from a single card on that particular result. It is in this graph that you can see interesting data about runts, drops, average frame rate and the actual frame rate of your gaming experience.

For tests that show no runts or drops, the data is pretty clean. This is the standard frame rate per second over a span of time graph that has become the standard for performance evaluation on graphics cards.

A test that does have runts and drops will look much different. The black bar labeled FRAPS indicates the average frame rate over time that traditional testing would show if you counted the drops and runts in the equation – as FRAPS FPS measurement does. Any area in red is a dropped frame – the wider the amount of red you see, the more colored bars from our overlay were missing in the captured video file, indicating the gamer never saw those frames in any form.

The wide yellow area is the representation of runts, the thin bands of color in our captured video, that we have determined do not add to the animation of the image on the screen. The larger the area of yellow the more often those runts are appearing.

Finally, the blue line is the measured FPS over each second after removing the runts and drops. We are going to be calling this metric the “observed frame rate” as it measures the actual speed of the animation that the gamer experiences.

The PERcentile File

Scott introduced the idea of frame time percentiles months ago but now that we have some different data using direct capture as opposed to FRAPS, the results might be even more telling. In this case, FCAT is showing percentiles not by frame time but instead by instantaneous FPS. This will tell you the minimum frame rate that will appear on the screen at any given percent of time during our benchmark run. The 50th percentile should be very close to the average total frame rate of the benchmark but as we creep closer to the 100% we see how the frame rate will be affected.

The closer this line is to being perfectly flat the better as that would mean we are running at a constant frame rate the entire time. A steep decline on the right hand side tells us that frame times are varying more and more frequently and might indicate potential stutter in the animation.

The PCPER Frame Time Variance File

Of all the data we are presenting, this is probably the one that needs the most discussion. In an attempt to create a new metric for gaming and graphics performance, I wanted to try to find a way to define stutter based on the data sets we had collected. As I mentioned earlier, we can define a single stutter as a variance level between t_game and t_display. This variance can be introduced in t_game, t_display, or on both levels. Since we can currently only reliably test the t_display rate, how can we create a definition of stutter that makes sense and that can be applied across multiple games and platforms?

We define a single frame variance as the difference between the current frame time and the previous frame time – how consistent the two frames presented to the gamer. However, as I found in my testing plotting the value of this frame variance is nearly a perfect match to the data presented by the minimum FPS (PER) file created by FCAT. To be more specific, stutter is only perceived when there is a break from the previous animation frame rates.

Our current running theory for a stutter evaluation is this: find the current frame time variance by comparing the current frame time to the running average of the frame times of the previous 20 frames. Then, by sorting these frame times and plotting them in a percentile form we can get an interesting look at potential stutter. Comparing the frame times to a running average rather than just to the previous frame should prevent potential problems from legitimate performance peaks or valleys found when moving from a highly compute intensive scene to a lower one.

While we are still trying to figure out if this is the best way to visualize stutter in a game, we have seen enough evidence in our game play testing and by comparing the above graphic to other data generated through our Frame rating system to be reasonably confident in our assertions. So much in fact that I am going to going this data the PCPER ISU, which beer fans will appreciate the acronym of International Stutter Units.

To compare these results you want to see a line that is as close the 0ms mark as possible indicating very little frame rate variance when compared to a running average of previous frames. There will be some inevitable incline as we reach the 90+ percentile but that is expected with any game play sequence that varies from scene to scene. What we do not want to see is a sharper line up that would indicate higher frame variance (ISU) and could be an indication that the game sees microstuttering and hitching problems.

Does the new frame pacing setting apply to just the Radeon 7000 series parts or will owners of 6000 series (or perhaps older) cards also benefit? I ask as an interested dual 6970 user, and I haven't really seen anyone talking about anything but 7000 series parts.

* Practice lifting (reading) smaller weight (difficulty) first.
* Do some workouts (skim the Article, and read the suggested backlinks that offer more info) to build up your strength.
* Go back and do more exercise, both when tired and not.
* Practice and take breaks.

That WILL make your Brain hurt, just like exercise makes your Muscles ache; same reason, the same benefit.

Your Brain will hurt less and less as the years pass, and you will be as fast as Bruce Lee (but not at Kung Fu unless you practice that in between reading Technical Materials).

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during his or her safety. Therefore, cyclists can suffer from Patellofemoral pain or Runner's knee syndrome.

You exaggerate a little with the last Sleeping Dogs graphs. The important question is: can a gamer perceive a 5ms variance at below 25ms?? I think the answer is NO.
Sleeping Dogs feels just as smooth on the 7990 as on the 690.

I just the the way the review reveals pretty much everything that AMD is still hiding on the new driver. Don't get me wrong, I'm an APU user; I'm greatly affected by this issue myself... albeit in a small scale.

Congratulations in proving you had solid data on the issue and in making AMD see this was something they needed to address. Also, congratulations on this amazing in-depth analysis of the new driver. It's really well laid-out and very thorough. Excellent work. This is the kind of stuff that keeps me coming back to see the content you produce.

I have said it before and I say it again: This frame-pacing, frame-pacing, FCAT or whatever you want to call the methodology, was the biggest step in gaming and GPU industry since DirectX 9 came along. And Ryan deserves﻿ a lot of credit for picking up from what Tech Report's has done and giving it an all new dimension, to the point AMD couldn't ignore it anymore. THIS IS A MAJOR WIN FOR US, THE GAMING COMMUNITY.
I'm glad this is out but, I only wish this were here sooner, when I had my HD4870X2 back in 2008 or my 2x HD4890 in 2009 or my HD5970 in 2010. After 5 years, I was burnt out and move on to a single-GPU card and got the best one I could afford, a GTX780. We can't have it all, I suppose.

Easy way to test it to go to a benchmark and run it with it off. Pay attention to screen tearing on the background more so then fps and numbers. If you notice the jitter go away when you turn it on and run the same thing, then it works. If not... well... not.

This does make a big difference on my dual 6950s. One easy quick way to notice the difference is to use MSI Kombuster DK11 and turn frame pacing on and off. So that's good, but really except for a few very recent games this fix isn't all that great for me. I don't really think crossfire or sli is a big deal for single screen resolutions. I'm glad AMD is addressing the issue, but it's a very obvious problem, and it's irritating some other review sites didn't mention how obviously bad Eyefinity and Crossifre work with each other. Gaming across 3 monitors is really an awesome experience, and I imagine so is 4k.

I installed this and battlefield 3 seems to be running much smoother for me. There was always the feeling that something was off playing that game but now the whole experience just feels much smoother.

Hey Ryan, good read.
I would just like to point out that since you cannot play on tiled 4K monitors with any Nvidia GeForce card ( they do not support dual monitor surround) means that the 7990 is in fact the fastest solution for 60hz 4K, because The Titan, 780, 690 and any GeForce card for that matter cannot be used in dual monitor surround.

This does make a big difference on my dual 6950s. One easy quick way to notice the difference is to use MSI Kombuster DK11 and turn frame pacing on and off. So that's good, but really except for a few very recent games this fix isn't all that great for me. I don't really think crossfire or sli is a big deal for single screen resolutions. I'm glad AMD is addressing the issue, but it's a very obvious problem, and it's irritating some other review sites didn't mention how obviously bad Eyefinity and Crossifre work with each other. Gaming across 3 monitors is really an awesome experience, and I imagine so is 4k.

This does make a big difference on my dual 6950s. One easy quick way to notice the difference is to use MSI Kombuster DK11 and turn frame pacing on and off. So that's good, but really except for a few very recent games this fix isn't all that great for me. I don't really think crossfire or sli is a big deal for single screen resolutions. I'm glad AMD is addressing the issue, but it's a very obvious problem, and it's irritating some other review sites didn't mention how obviously bad Eyefinity and Crossifre work with each other. Gaming across 3 monitors is really an awesome experience, and I imagine so is 4k.

Nice article! Only it lacks Bioshock Infinite wich i can say is much smoother now(with two 7950s here), but still not perfect or very acceptable and frame tearing is also there. Also i wonder if microstuttering and tearing on hight solid framerates are connected

Just bear in mind that Bioshock Infinite's engine has a stuttering problem all by itself regardless of what GPU you are using.

Tearing is a completely different and well understood issue that happens most commonly at above 60 FPS (or whatever the refresh rate of your monitor is). V-Sync is the fix for tearing, but it can add some input lag depending on how it is implemented.

Just bear in mind that Bioshock Infinite's engine has a stuttering problem all by itself regardless of what GPU you are using.

Tearing is a completely different and well understood issue that happens most commonly at above 60 FPS (or whatever the refresh rate of your monitor is). V-Sync is the fix for tearing, but it can add some input lag depending on how it is implemented.

The reason I ask is because it looks from the graphs that AMD might be using a threshold based algorithm that only kicks in when a certain amount of adjustment is required. This would result in the stepping you are seeing and I am fairly certain that with a bit of signal analysis and some custom software that I can determine what the likely threshold is if there is one.

AMD should have added you to their payroll for exposing this. It is >>tragic<< for a manufacturer not to have tested the true display performance of their cards and having a reviewer showing them how it' s done. Unacceptable.-

Dear amd, I thank you that the "secreted" anal hammering you have been delivering for years and swore you weren't doing has been reduced, even though it took many beatings and incarcerations before you owned up to your problem.
We don't know if you are stupid or blind or both, or just a liar.
Since you likely have 4 or 5 other major secrets right now just like the runts you anal hammered on everyone for years while in public denial, this is not a real thank you, it is just a reminder about who and what you really are.

I've got a 6990 with an arctic cooling cooler on it.
I've also got shit eyes and can't seem to notice any difference yet. Farcry 3 still plays like crap and my golf gti exhaust is still blowing balls, but hey.
I'm very happy AMD are listening and gradually sorting this problem out, I just wish they would be more pro active instead of sorting shit out when people call them out.

Great work! And great review! I hope AMD will take a look at Dual Graphics issue. Because this release doesn't affect Dual Graphics. And It's really annoying, coz It's great deal for notebooks, there is just no contest for AMD A10-4600M(7660G+7690M) combo for that money and productivity. So please aks AMD about Dual Graphics issue. I believe in you.

I have a 7970 crossfire setup. The rest of my computer is listed below: I7 4770k factory speed, gigabyte GA-Z87X-UD3H motherboard, 16gb ram, 650w 80+ gold psu, windows 7 x64. When i try running BF3 with the 13.8 beta driver, I get black thick bands flashing horizontally across my screen, sometimes immediately and sometimes after 5-10 minutes. My game would then crash and I would then get static artifacts of squares with little squares in them with the error titled: Directx Function Get Device Removed Reason. Any help would be much appreciated.